Foliar fungicide application to maize: Yield and grain hardness enhancement in different environmental conditions

The dry milling industry is becoming an interesting distribution channel for maize, [Zea mays (L.)] growers. Since kernels with high hardness are more suitable for the dry milling process, it is important to investigate new ways of improving for this qualitative parameter. The aim of the research was to evaluate when a fungicide containing a Demethylation inhibitor and a Quinone outside inhibitor could be effective in controlling fungal disease, increasing grain yield and improving kernel hardness. A mixture of azoxystrobin and propiconazole was tested at two locations from 2009 to 2012, with two application timings: the beginning of stem elongation and at tassel emergence. The two fungicide timings significantly reduced the incidence of Northern Corn Leaf Blight symptoms, a foliar disease caused by Exserohilum turcicum, by respectively 30% and 61%. A significant increase of grain yield (between 5-7%) and kernel hardness was obtained in both sites by this compound application mainly when the environmental conditions led to a gradual grain filling. The best result was obtained always for the application at the tassel emergence stage; this treatment could contribute to increase competitiveness in maize production systems, especially for the dry milling uses.